On Wed, Jan 8, 2025 at 11:42 AM Andrew Dunstan <and...@dunslane.net> wrote:
> > On 2025-01-07 Tu 2:44 PM, Mats Kindahl wrote: > > I got some time over during the holidays, so I spent some of it > > doing something I've been thinking about for a while. > > > > For those of you that are not aware of it: Coccinelle is a tool for > > pattern matching and text transformation for C code and can be used > > for detection of problematic programming patterns and to make complex, > > tree-wide patches easy. It is aware of the structure of C code and is > > better suited to make complicated changes than what is possible using > > normal text substitution tools like Sed and Perl. > > > > Coccinelle have been successfully been used in the Linux project since > > 2008 and is now an established tool for Linux development and a large > > number of semantic patches have been added to the source tree to > > capture everything from generic issues (like eliminating the redundant > > A in expressions like "!A || (A && B)") to more Linux-specific > > problems like adding a missing call to kfree(). > > > > Although PostgreSQL is nowhere the size of the Linux kernel, it is > > nevertheless of a significant size and would benefit from > > incorporating Coccinelle into the development. I noticed it's been > > used in a few cases way back (like 10 years back) to fix issues in the > > PostgreSQL code, but I thought it might be useful to make it part of > > normal development practice to, among other things: > > > > - Identify and correct bugs in the source code both during development > > and review. > > - Make large-scale changes to the source tree to improve the code > > based on new insights. > > - Encode and enforce APIs by ensuring that function calls are used > > correctly. > > - Use improved coding patterns for more efficient code. > > - Allow extensions to automatically update code for later PostgreSQL > > versions. > > > > To that end, I created a series of patches to show how it could be > > used in the PostgreSQL tree. It is a lot easier to discuss concrete > > code and I split it up into separate messages since that makes it > > easier to discuss each individual patch. The series contains code to > > make it easy to work with Coccinelle during development and reviews, > > as well as examples of semantic patches that capture problems, > > demonstrate how to make large-scale changes, how to enforce APIs, and > > also improve some coding patterns. > > > > This first patch contains the coccicheck.py script, which is a > > re-implementation of the coccicheck script that the Linux kernel uses. > > We cannot immediately use the coccicheck script since it is quite > > closely tied to the Linux source code tree and we need to have > > something that both supports autoconf and Meson. Since Python seems to > > be used more and more in the tree, it seems to be the most natural > > choice. (I have no strong opinion on what language to use, but think > > it would be good to have something that is as platform-independent as > > possible.) > > > > The intention is that we should be able to use the Linux semantic > > patches directly, so it supports the "Requires" and "Options" > > keywords, which can be used to require a specific version of spatch(1) > > and add options to the execution of that semantic patch, respectively. > > > > > Please don't start multiple threads like this. If you want to submit a > set of patches for a single feature, send them all as attachments in a > single email. Otherwise this just makes life hard for threading email > readers. > My apologies, I thought this would make it easier to discuss and review the code. I will send a single email in the future. Should I resend this as a single email with all the patches? -- Best wishes, Mats Kindahl, Timescale
